Shock-absobbeb



E. W. HOFSTATTER.

SHOOKABSORBEB. `luluclqllon mfp mu 29. ma.

Patented Ang. 26, 1919.

STATES PATENT oEEioE.

ERNEST W. HOFSTATEB, F ACK; NEW YORK.

SHOCK-Assouline.

imanes.

To all whom t may concern:

Be it known that I, ERNEST W. HoFs'rA'r- TER, a citizen of the United States, residing at Nyack, in the county of Rockland and State of New York, have invented certain new and useful Improvements in Shock- Absorbers.; and I do declare the following to be a'full, clear, and exact description of the l invention, such as will enable others skilled normal position.

in the artto which it appertains to make and use thesame.

This' invention relates to an improved shock absorber and recoil check, and it relates more particularly to an improved pneumatic device for cushioning or absorbing the shocks consequent to the traveling of fautomobiles and the like.

One of the objects of this invention is to y provide a shock absorber which is equally effective to counteract a shock or motion in a-given direction and in'the opposite direction.

Another object is to provide a shock absorber which counteracts shocks by simultaneously creating a partial vacuum and a compression of air. l

Another objectis to provide a pneumatic shock absorber in which the air pressure is relieved immediately after the shock has been counteracted or cushioned, so as to al- 'low free play of the main membeisin re- -lation .to one another, in the direction of motion, but to check the recoil of same until car and 'spring have returned to lnormal position.

Another object is to check recoil of the main members vin either direction back to Another object is to provide a device of this character which is of very simple construction, comparatively inexpensive, ca sy to apply, and not likely to get out of repair.

Other objects and advantages ma become apparent to persons who read the ollowing Adetails of description in connection with the appendedadrawings in whichl Fi-gurel is a longitudinal sectional v'iew cfa 'shock absorber constructed in accordance with oneemlbodiment of this invention; is a transverse sectional view along theirs@ 2*.-2 of Fig. 1;

A Specification of Letters Patent. Application led July 29, 1918. SerialNo. 247,259.

Patented Aug. 26, i919.

9, and the elements 7, 8 and 9 constitute a member which closes one end of a cylindrical air chamber 10. The other end of this air chamber is closedby means of a cylinder head or cap 11 which is provided with a stuffing box 12 through which a piston rod 13 extends. The piston rod is provided with a bearing element 14, adapted for connection with any moving part of the automobile' or other vehicle, and a piston head 15 is secured on the other end of rod 13.

A cylinder or valve chamber 16 is referably cast integrally with the cylin er 10, and coextensive therewith in length, and is spaced therefrom by means of a partition 17,

the rod being provided with a central port,

18 and end ports 19, these ports establishing communication between` the cylinders or chambers 10 and 16. Caps or cylinder heads 20 close the ends of the chamber 16, these caps being preferably secured by means of screw threads thereon which engage with internal screw threads `of cylinder 16. The screw-threaded portions of cylinder 16 extend inward a considerable distance beyond the ports 19, and'valve members 21 are secured within the ends of cylinder 16 by means of these internal screw threads eni gagging with external screw threads which extend throughout the length of the valve members. Each of the cylindrical valve members 21 is provided with 'apertured guides 22 through which a valve stem' 23is mounted to reciprocate. On one end of each valve stem 23 is mounted an apertured valve closin member 24, the apertures 25 of which are re atively small, the aggregate capacity' of the apertures 25 in each va1ve`closin member' 24 beingless than the capabity o either of the poi-ts 19, so that the air cannot escape ilu-ouch the apertures' tast as it enters either oi the cylindrical valve members through. either of the ports 19; and flwrefore. each valve is opened and closed according to the amount andldirection of air pressure thcrcagainst. lach vaive stem :23 is provided with a. head or shoulder 26, and a spring 27 is provided for each valvestein, said spring being intcriioscd between the head 26 and the guides 22 of eac-h valve. From the foregoing, it will be seen that each valve comprises one each of the elements 21,

23, Q4, :2G and 27, and two oi" the guides 22, these valves being unitary structures which are capable Yoli bodily attachmentand detachment with relation to the cylinder 16, and therefore, in case of failure of one of the valves, it may be removed and replaced with ,comparatively little expense andI 1nconvenience This arrangement also avoids the delays which would be occasioned by the grinding 4of stationary valve seatsL The port 18 is of considerably'greater ca-` pacity than either of the ports 1S), but its size is such with relation to those of the piston that the latter extends a considerable distancebeyond saidport 18, in all direc'- tions, when the piston is in its normal or centralv position. Therefore as air cannot `pass through tport 18 until the piston has moved 'a considerable distance 1n either dr rection4 alongfits action, and iii-thus moving along itsaction, the piston tends to create afvacuum 1n one of the cylinders 1() While pressing air inthe other end thereof. However, the conipressing of air is not confinedl to the ylinderlO, but also takes place in the cylind" 1 16, because the air passes through one off'fthe ports 19 into the adjusting end oin the cylinder 16 and then passes through the valve member 21 and moves the valve closure to itsopen position, since the ports 9.5 are insuliicient to accommodate the air which passes through -port 19. A portion of the air being' compressed in the cylinder. 16

passes through'the' apertures 25 in 'the opposite valve closureand passes thence through the other port l19 into the cylinder 1'0 so that' the partial vacuum is'A somewhat relieved.` The relief ofthe partial vacuum, hwevcr', is`

ratherslow and gradual, and completel relief 1s notl obtained -until the piston'has moved v suiliciently -far to open the port 1S. In the meantimev the shock' has been relieved by y' the combined pressurei and partial vacuum acting uponthe 'piston'115, and the greatest efficiency has thus been obtained; but novi/fit is `desirable that .the recoil belchecked and thepiston allowed to return to` normal position gradually, and this action is vmitomati' 4 cally effected through the medium of fthe" apertured "valve closing membersQ-t, the air passing,y through the v apertures 25 so as ,tot partition separating lind its equilibrium on opposite sides orm the piston 15. In order that this device may be kept well lubricated Without more than occasional attention. I form the upper end of the piston 15 with anapertu'redg annular flange which combines niththehorizontal upper end ot r thc piston rto form an oil-'pan and wick holder. Wicks 28 are contained respectively in apertures .through inwardly or radiallyextending bosses 28', andthese Wicks lead oil from the top lof the, piston to the convexed side thereof and to thecon tiguous Wall of the cylinder, thereby thoroughly lubricating these Working surfaces.

A screw-plug 30 is providedinr the upper Working cylinder-head forthe oil to be introduced into ythe cylinder.`

f VFrom theL foregoing, it-will be seen that I have provided' a devicel of very'` simple andu practical construction,` and which is fully capable of attaining thev foregoing objects.

Although Ihave described thisembodi@ mediary port and end ports which estab? lish a communication between said air chambers, a piston in said main air chamber, a pair of valve guides in opposite endsoi said subsidiary chamber and alined With one an i other,and a pair of apertured valve-closing members each being disposed in one of saidy guides and operable"v to lesssen the low'of air by their movement away from one another, the apertures of said* valveclosing members remaining open at all times.

2. A shock absorber comprising amain air chamber, al subsidiary airchamber, a.

partition separatingsaid main and subsidiary chambers and provided With an intermediary port andnend ports Which establish a communication betWeecn said air chambers, apist'on in ,sad 'mainair chamber and having an axial lingth suliicient to completely close Saidtcentral port, and a pair of check valves eachldisposedin one end oi said subsidiary chamber;- said piston being normally positioned to close said central port and being capable of opening said central port when moved in either directionbeyond its normal position.

3. A shock absorbercomprisingl a.. main airjchamber, 'a subsidiary air chamber, a. f said mam .and subsidi# aryA chamberS and provided with an 'Inter mediary port and end ports Whchesmblsh a communication between said air chambers,

a pistonl in said main nir chamber, tubular Kmembers `each 'formed with a vulve scat and bemg removably secured m cnc cml of said subsidiary chamber, between the said end ports, und valve closlng members, euch movubly seculcd in one of fud tubular uwmbvlzs my hund.

ERNEST W. HOFSTATTER. 

